Feature: Use dbt-core starter project as baseline for split projects

dbt_meshify/change.py

@@ -2,7 +2,7 @@
 import os
 from enum import Enum
 from pathlib import Path
-from typing import Dict, Iterable, List, Optional, Protocol
+from typing import Callable, Dict, Iterable, List, Optional, Protocol
 
 
 class Operation(str, Enum):
@@ -46,6 +46,7 @@ class EntityType(str, Enum):
     SemanticModel = "semantic_model"
     Project = "project"
     Code = "code"
+    Directory = "directory"
 
     def pluralize(self) -> str:
         if self is self.Analysis:
@@ -97,6 +98,14 @@ def __str__(self):
         )
 
 
+@dataclasses.dataclass
+class DirectoryChange(BaseChange):
+    """A DirectoryChange represents a unit of work that should be performed on a Directory in a dbt project."""
+
+    source: Optional[Path] = None
+    ignore_function: Optional[Callable] = None
+
+
 @dataclasses.dataclass
 class FileChange(BaseChange):
     """A FileChange represents a unit of work that should be performed on a File in a dbt project."""

dbt_meshify/change_set_processor.py

@@ -4,7 +4,14 @@
 from loguru import logger
 
 from dbt_meshify.change import Change, ChangeSet, EntityType
-from dbt_meshify.storage.file_content_editors import RawFileEditor, ResourceFileEditor
+from dbt_meshify.storage.file_content_editors import (
+    DirectoryEditor,
+    RawFileEditor,
+    ResourceFileEditor,
+)
+
+# Enumeration of valid File Editors
+FILE_EDITORS = {EntityType.Code: RawFileEditor, EntityType.Directory: DirectoryEditor}
 
 
 class ChangeSetProcessorException(BaseException):
@@ -24,9 +31,7 @@ def __init__(self, dry_run: bool = False) -> None:
 
     def write(self, change: Change) -> None:
         """Commit a Change to the file system."""
-        file_editor = (
-            RawFileEditor() if change.entity_type == EntityType.Code else ResourceFileEditor()
-        )
+        file_editor = FILE_EDITORS.get(change.entity_type, ResourceFileEditor)()
 
         file_editor.__getattribute__(change.operation)(change)
 

dbt_meshify/storage/dbt_project_editors.py

@@ -1,4 +1,6 @@
+import shutil
 from pathlib import Path
+from tracemalloc import start
 from typing import Dict, Optional, Set
 
 from dbt.contracts.graph.nodes import (
@@ -12,9 +14,11 @@
 )
 from dbt.node_types import AccessType
 from loguru import logger
+from regex import D
 
 from dbt_meshify.change import (
     ChangeSet,
+    DirectoryChange,
     EntityType,
     FileChange,
     Operation,
@@ -30,6 +34,20 @@
 from dbt_meshify.utilities.references import ReferenceUpdater
 
 
+def get_starter_project_path() -> Path:
+    """Obtain the path of a dbt starter project on the local filesystem."""
+
+    from importlib import resources
+
+    import dbt.include.starter_project
+
+    starter_path = Path(str(resources.files(dbt.include.starter_project)))
+    assert starter_path is not None
+    assert (starter_path / "dbt_project.yml").exists()
+
+    return starter_path
+
+
 class DbtSubprojectCreator:
     """
     Takes a `DbtSubProject` and creates the directory structure and files for it.
@@ -85,14 +103,29 @@ def _get_subproject_boundary_models(self) -> Set[str]:
         )
         return boundary_models
 
+    def create_starter_project(self) -> DirectoryChange:
+        """Create a new starter project using the default stored in dbt-core"""
+
+        return DirectoryChange(
+            operation=Operation.Copy,
+            entity_type=EntityType.Directory,
+            identifier=str(self.subproject.path),
+            path=self.subproject.path,
+            source=get_starter_project_path(),
+            ignore_function=shutil.ignore_patterns("__init__.py", "__pycache__", "**/*.pyc"),
+        )
+
     def write_project_file(self) -> FileChange:
         """
         Writes the dbt_project.yml file for the subproject in the specified subdirectory
         """
+
+        # Read a starter `dbt_project.yml` file as a baseline
+        starter_path: Path = get_starter_project_path() / "dbt_project.yml"
+        starter_dbt_project = YAMLFileManager.read_file(starter_path)
+
         contents = self.subproject.project.to_dict()
-        # was getting a weird serialization error from ruamel on this value
-        # it's been deprecated, so no reason to keep it
-        contents.pop("version")
+
         # this one appears in the project yml, but i don't think it should be written
         contents.pop("query-comment")
         contents = filter_empty_dict_items(contents)
@@ -105,12 +138,22 @@ def write_project_file(self) -> FileChange:
             if max([len(version) for version in contents["require-dbt-version"]]) == 1:
                 contents["require-dbt-version"] = "".join(contents["require-dbt-version"])
 
+        for key, value in contents.items():
+            if value is None:
+                continue
+
+            if isinstance(value, (list, dict, tuple)):
+                if len(value) == 0:
+                    continue
+
+            starter_dbt_project[key] = value
+
         return FileChange(
             operation=Operation.Add,
             entity_type=EntityType.Code,
             identifier="dbt_project.yml",
             path=self.subproject.path / Path("dbt_project.yml"),
-            data=yaml.dump(contents),
+            data=yaml.dump(starter_dbt_project),
         )
 
     def copy_packages_yml_file(self) -> FileChange:
@@ -143,6 +186,8 @@ def initialize(self) -> ChangeSet:
             f"Identifying operations required to split {subproject.name} from {subproject.parent_project.name}."
         )
 
+        change_set.add(self.create_starter_project())
+
         for unique_id in (
             subproject.resources
             | subproject.custom_macros

dbt_meshify/storage/file_content_editors.py

@@ -2,9 +2,13 @@
 
 from loguru import logger
 
-from dbt_meshify.change import EntityType, FileChange, ResourceChange
+from dbt_meshify.change import DirectoryChange, EntityType, FileChange, ResourceChange
 from dbt_meshify.exceptions import FileEditorException
-from dbt_meshify.storage.file_manager import RawFileManager, YAMLFileManager
+from dbt_meshify.storage.file_manager import (
+    DirectoryManager,
+    RawFileManager,
+    YAMLFileManager,
+)
 
 
 class NamedList(dict):
@@ -89,6 +93,18 @@ def safe_update(original: Dict[Any, Any], update: Dict[Any, Any]) -> Dict[Any, A
     return original
 
 
+class DirectoryEditor:
+    """A helper class used to perform filesystem operations on Directories"""
+
+    @staticmethod
+    def copy(change: DirectoryChange):
+        """Copy a file from one location to another."""
+        if change.source is None:
+            raise FileEditorException("None source value provided in Copy operation.")
+
+        DirectoryManager.copy_directory(change.source, change.path, change.ignore_function)
+
+
 class RawFileEditor:
     """A class used to perform Raw operations on Files"""
 

dbt_meshify/storage/file_manager.py

@@ -3,7 +3,7 @@
 
 import shutil
 from pathlib import Path
-from typing import Any, Dict, List, Protocol
+from typing import Any, Callable, Dict, List, Optional, Protocol
 
 from dbt.contracts.util import Identifier
 from ruamel.yaml import YAML
@@ -18,6 +18,7 @@ def __init__(self):
         self.preserve_quotes = True
         self.width = 4096
         self.indent(mapping=2, sequence=4, offset=2)
+        self.default_flow_style = False
 
     def dump(self, data, stream=None, **kw):
         inefficient = False
@@ -43,6 +44,21 @@ def write_file(self, path: Path, content: Any) -> None:
         pass
 
 
+class DirectoryManager:
+    """DirectoryManager is a FileManager for operating on directories in the filesystem"""
+
+    @staticmethod
+    def copy_directory(
+        source_path: Path, target_path: Path, ignore_function: Optional[Callable] = None
+    ) -> None:
+        """Copy a directory from source to target"""
+
+        if not target_path.parent.exists():
+            target_path.parent.mkdir(parents=True, exist_ok=True)
+
+        shutil.copytree(source_path, target_path, symlinks=True, ignore=ignore_function)
+
+
 class RawFileManager:
     """RawFileManager is a FileManager for operating on raw files in the filesystem."""